| Message ID | 20240808154237.220029-5-pasha.tatashin@soleen.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Fixes for memmap accounting | expand |
> #ifdef CONFIG_COMPACTION > > struct contig_page_info { > @@ -1255,11 +1272,11 @@ const char * const vmstat_text[] = { > "pgdemote_kswapd", > "pgdemote_direct", > "pgdemote_khugepaged", > - "nr_memmap", > - "nr_memmap_boot", > /* system-wide enum vm_stat_item counters */ > "nr_dirty_threshold", > "nr_dirty_background_threshold", > + "nr_memmap", > + "nr_memmap_boot", While we're at it (sorry, I should have found more time revieweing this earlier!) ... What is the unit here? Should this be "nr_memmap_pages" / "nr_memmap_boot_pages"? Like $ cat /proc/vmstat | grep pages nr_free_pages 3618323 nr_zspages 3 nr_anon_pages 1053316 nr_file_pages 3199210 nr_shmem_hugepages 546 nr_file_hugepages 0 nr_anon_transparent_hugepages 0 nr_page_table_pages 15215 nr_sec_page_table_pages 0 numa_pages_migrated 0 Nothing else jumped at me.
On Thu, Aug 08, 2024 at 03:42:37PM +0000, Pasha Tatashin wrote: > Currently, when memory is hot-plugged or hot-removed the accounting is > done based on the assumption that memmap is allocated from the same node > as the hot-plugged/hot-removed memory, which is not always the case. > > In addition, there are challenges with keeping the node id of the memory > that is being remove to the time when memmap accounting is actually > performed: since this is done after remove_pfn_range_from_zone(), and > also after remove_memory_block_devices(). Meaning that we cannot use > pgdat nor walking though memblocks to get the nid. > How about directly include the failing cases and user visible impacts as reported in the Tags appended below. --Alison > Given all of that, account the memmap overhead system wide instead. > > For this we are going to be using global atomic counters, but given that > memmap size is rarely modified, and normally is only modified either > during early boot when there is only one CPU, or under a hotplug global > mutex lock, therefore there is no need for per-cpu optimizations. > > Reported-by: Yi Zhang <yi.zhang@redhat.com> > Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com > Reported-by: Alison Schofield <alison.schofield@intel.com> > Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t > > Fixes: 15995a352474 ("mm: report per-page metadata information") > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> > --- snip >
On Thu, Aug 8, 2024 at 2:26 PM David Hildenbrand <david@redhat.com> wrote: > > > #ifdef CONFIG_COMPACTION > > > > struct contig_page_info { > > @@ -1255,11 +1272,11 @@ const char * const vmstat_text[] = { > > "pgdemote_kswapd", > > "pgdemote_direct", > > "pgdemote_khugepaged", > > - "nr_memmap", > > - "nr_memmap_boot", > > /* system-wide enum vm_stat_item counters */ > > "nr_dirty_threshold", > > "nr_dirty_background_threshold", > > + "nr_memmap", > > + "nr_memmap_boot", > > While we're at it (sorry, I should have found more time revieweing this > earlier!) ... > > What is the unit here? Should this be "nr_memmap_pages" / > "nr_memmap_boot_pages"? Like > > $ cat /proc/vmstat | grep pages > nr_free_pages 3618323 > nr_zspages 3 > nr_anon_pages 1053316 > nr_file_pages 3199210 > nr_shmem_hugepages 546 > nr_file_hugepages 0 > nr_anon_transparent_hugepages 0 > nr_page_table_pages 15215 > nr_sec_page_table_pages 0 > numa_pages_migrated 0 > > > Nothing else jumped at me. Good idea, I will add _pages
On Thu, Aug 8, 2024 at 2:55 PM Alison Schofield <alison.schofield@intel.com> wrote: > > On Thu, Aug 08, 2024 at 03:42:37PM +0000, Pasha Tatashin wrote: > > Currently, when memory is hot-plugged or hot-removed the accounting is > > done based on the assumption that memmap is allocated from the same node > > as the hot-plugged/hot-removed memory, which is not always the case. > > > > In addition, there are challenges with keeping the node id of the memory > > that is being remove to the time when memmap accounting is actually > > performed: since this is done after remove_pfn_range_from_zone(), and > > also after remove_memory_block_devices(). Meaning that we cannot use > > pgdat nor walking though memblocks to get the nid. > > > > How about directly include the failing cases and user visible impacts as > reported in the Tags appended below. Do you mean adding panic backtraces or repro steps to the commit log?
On Thu, Aug 08, 2024 at 03:05:32PM -0400, Pasha Tatashin wrote: > On Thu, Aug 8, 2024 at 2:55 PM Alison Schofield > <alison.schofield@intel.com> wrote: > > > > On Thu, Aug 08, 2024 at 03:42:37PM +0000, Pasha Tatashin wrote: > > > Currently, when memory is hot-plugged or hot-removed the accounting is > > > done based on the assumption that memmap is allocated from the same node > > > as the hot-plugged/hot-removed memory, which is not always the case. > > > > > > In addition, there are challenges with keeping the node id of the memory > > > that is being remove to the time when memmap accounting is actually > > > performed: since this is done after remove_pfn_range_from_zone(), and > > > also after remove_memory_block_devices(). Meaning that we cannot use > > > pgdat nor walking though memblocks to get the nid. > > > > > > > How about directly include the failing cases and user visible impacts as > > reported in the Tags appended below. > > Do you mean adding panic backtraces or repro steps to the commit log? Yes. Perhaps abbreviated but something that makes the connection, like this: ndctl users reported a GPF when trying to destroy a namespace: # ndctl destroy-namespace all -r all -f Segmentation fault dmesg: [] Oops: general protection fault, probably for non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN PTI [] KASAN: probably user-memory-access in range [0x000000000002b280-0x000000000002b287] [] CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1 [] Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS 2.20.1 09/13/2023 [] RIP: 0010:mod_node_page_state+0x2a/0x110 cxl-test users report a GPF when trying to unload the test module: # modrpobe -r cxl-test dmesg [] BUG: unable to handle page fault for address: 0000000000004200 [] #PF: supervisor read access in kernel mode [] #PF: error_code(0x0000) - not-present page [] PGD 0 P4D 0 [] Oops: Oops: 0000 [#1] PREEMPT SMP PTI [] CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197 [] Tainted: [O]=OOT_MODULE, [N]=TEST [] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 [] RIP: 0010:mod_node_page_state+0x6/0x90
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 41458892bc8a..1dc6248feb83 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -220,8 +220,6 @@ enum node_stat_item { PGDEMOTE_KSWAPD, PGDEMOTE_DIRECT, PGDEMOTE_KHUGEPAGED, - NR_MEMMAP, /* page metadata allocated through buddy allocator */ - NR_MEMMAP_BOOT, /* page metadata allocated through boot allocator */ NR_VM_NODE_STAT_ITEMS }; diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 9ab4fa5e09b5..596c050ed492 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -38,6 +38,8 @@ struct reclaim_stat { enum vm_stat_item { NR_DIRTY_THRESHOLD, NR_DIRTY_BG_THRESHOLD, + NR_MEMMAP, /* page metadata allocated through buddy allocator */ + NR_MEMMAP_BOOT, /* page metadata allocated through boot allocator */ NR_VM_STAT_ITEMS, }; @@ -618,7 +620,6 @@ static inline void lruvec_stat_sub_folio(struct folio *folio, lruvec_stat_mod_folio(folio, idx, -folio_nr_pages(folio)); } -void __meminit mod_node_early_perpage_metadata(int nid, long delta); -void __meminit store_early_perpage_metadata(void); - +void mod_memmap_boot(long delta); +void mod_memmap(long delta); #endif /* _LINUX_VMSTAT_H */ diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 70027869d844..60a5faa1f341 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -185,10 +185,10 @@ static int vmemmap_remap_range(unsigned long start, unsigned long end, static inline void free_vmemmap_page(struct page *page) { if (PageReserved(page)) { - mod_node_page_state(page_pgdat(page), NR_MEMMAP_BOOT, -1); + mod_memmap_boot(-1); free_bootmem_page(page); } else { - mod_node_page_state(page_pgdat(page), NR_MEMMAP, -1); + mod_memmap(-1); __free_page(page); } } @@ -341,7 +341,7 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end, copy_page(page_to_virt(walk.reuse_page), (void *)walk.reuse_addr); list_add(&walk.reuse_page->lru, vmemmap_pages); - mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, 1); + mod_memmap(1); } /* @@ -396,7 +396,7 @@ static int alloc_vmemmap_page_list(unsigned long start, unsigned long end, goto out; list_add(&page->lru, list); } - mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, nr_pages); + mod_memmap(nr_pages); return 0; out: diff --git a/mm/mm_init.c b/mm/mm_init.c index 75c3bd42799b..29677274e74e 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1623,8 +1623,7 @@ static void __init alloc_node_mem_map(struct pglist_data *pgdat) panic("Failed to allocate %ld bytes for node %d memory map\n", size, pgdat->node_id); pgdat->node_mem_map = map + offset; - mod_node_early_perpage_metadata(pgdat->node_id, - DIV_ROUND_UP(size, PAGE_SIZE)); + mod_memmap_boot(DIV_ROUND_UP(size, PAGE_SIZE)); pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n", __func__, pgdat->node_id, (unsigned long)pgdat, (unsigned long)pgdat->node_mem_map); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 28f80daf5c04..875d76e8684a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5755,7 +5755,6 @@ void __init setup_per_cpu_pageset(void) for_each_online_pgdat(pgdat) pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); - store_early_perpage_metadata(); } __meminit void zone_pcp_init(struct zone *zone) diff --git a/mm/page_ext.c b/mm/page_ext.c index 962d45eee1f8..a4b485b39330 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -214,8 +214,7 @@ static int __init alloc_node_page_ext(int nid) return -ENOMEM; NODE_DATA(nid)->node_page_ext = base; total_usage += table_size; - mod_node_page_state(NODE_DATA(nid), NR_MEMMAP_BOOT, - DIV_ROUND_UP(table_size, PAGE_SIZE)); + mod_memmap_boot(DIV_ROUND_UP(table_size, PAGE_SIZE)); return 0; } @@ -275,10 +274,8 @@ static void *__meminit alloc_page_ext(size_t size, int nid) else addr = vzalloc_node(size, nid); - if (addr) { - mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, - DIV_ROUND_UP(size, PAGE_SIZE)); - } + if (addr) + mod_memmap(DIV_ROUND_UP(size, PAGE_SIZE)); return addr; } @@ -330,14 +327,12 @@ static void free_page_ext(void *addr) if (is_vmalloc_addr(addr)) { page = vmalloc_to_page(addr); pgdat = page_pgdat(page); - mod_node_page_state(pgdat, NR_MEMMAP, - -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); + mod_memmap(-1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); vfree(addr); } else { page = virt_to_page(addr); pgdat = page_pgdat(page); - mod_node_page_state(pgdat, NR_MEMMAP, - -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); + mod_memmap(-1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); BUG_ON(PageReserved(page)); kmemleak_free(addr); free_pages_exact(addr, table_size); diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 1dda6c53370b..307f6fe83598 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -469,13 +469,10 @@ struct page * __meminit __populate_section_memmap(unsigned long pfn, if (r < 0) return NULL; - if (system_state == SYSTEM_BOOTING) { - mod_node_early_perpage_metadata(nid, DIV_ROUND_UP(end - start, - PAGE_SIZE)); - } else { - mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, - DIV_ROUND_UP(end - start, PAGE_SIZE)); - } + if (system_state == SYSTEM_BOOTING) + mod_memmap_boot(DIV_ROUND_UP(end - start, PAGE_SIZE)); + else + mod_memmap(DIV_ROUND_UP(end - start, PAGE_SIZE)); return pfn_to_page(pfn); } diff --git a/mm/sparse.c b/mm/sparse.c index e4b830091d13..9cc80ba1f7c1 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -463,7 +463,7 @@ static void __init sparse_buffer_init(unsigned long size, int nid) sparsemap_buf = memmap_alloc(size, section_map_size(), addr, nid, true); sparsemap_buf_end = sparsemap_buf + size; #ifndef CONFIG_SPARSEMEM_VMEMMAP - mod_node_early_perpage_metadata(nid, DIV_ROUND_UP(size, PAGE_SIZE)); + mod_memmap_boot(DIV_ROUND_UP(size, PAGE_SIZE)); #endif } @@ -643,8 +643,7 @@ static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, unsigned long start = (unsigned long) pfn_to_page(pfn); unsigned long end = start + nr_pages * sizeof(struct page); - mod_node_page_state(page_pgdat(pfn_to_page(pfn)), NR_MEMMAP, - -1L * (DIV_ROUND_UP(end - start, PAGE_SIZE))); + mod_memmap(-1L * (DIV_ROUND_UP(end - start, PAGE_SIZE))); vmemmap_free(start, end, altmap); } static void free_map_bootmem(struct page *memmap) diff --git a/mm/vmstat.c b/mm/vmstat.c index 6f8aa4766f16..896f9a2ace8a 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1033,6 +1033,23 @@ unsigned long node_page_state(struct pglist_data *pgdat, } #endif +/* + * Count number of pages "struct page" and "struct page_ext" consume. + * nr_memmap_boot: # of pages allocated by boot allocator & not part of MemTotal + * nr_memmap: # of pages that were allocated by buddy allocator + */ +static atomic_long_t nr_memmap_boot, nr_memmap; + +void mod_memmap_boot(long delta) +{ + atomic_long_add(delta, &nr_memmap_boot); +} + +void mod_memmap(long delta) +{ + atomic_long_add(delta, &nr_memmap); +} + #ifdef CONFIG_COMPACTION struct contig_page_info { @@ -1255,11 +1272,11 @@ const char * const vmstat_text[] = { "pgdemote_kswapd", "pgdemote_direct", "pgdemote_khugepaged", - "nr_memmap", - "nr_memmap_boot", /* system-wide enum vm_stat_item counters */ "nr_dirty_threshold", "nr_dirty_background_threshold", + "nr_memmap", + "nr_memmap_boot", #if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG) /* enum vm_event_item counters */ @@ -1827,6 +1844,8 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos) global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD, v + NR_DIRTY_THRESHOLD); + v[NR_MEMMAP_BOOT] = atomic_long_read(&nr_memmap_boot); + v[NR_MEMMAP] = atomic_long_read(&nr_memmap); v += NR_VM_STAT_ITEMS; #ifdef CONFIG_VM_EVENT_COUNTERS @@ -2285,25 +2304,3 @@ static int __init extfrag_debug_init(void) module_init(extfrag_debug_init); #endif - -/* - * Page metadata size (struct page and page_ext) in pages - */ -static unsigned long early_perpage_metadata[MAX_NUMNODES] __meminitdata; - -void __meminit mod_node_early_perpage_metadata(int nid, long delta) -{ - early_perpage_metadata[nid] += delta; -} - -void __meminit store_early_perpage_metadata(void) -{ - int nid; - struct pglist_data *pgdat; - - for_each_online_pgdat(pgdat) { - nid = pgdat->node_id; - mod_node_page_state(NODE_DATA(nid), NR_MEMMAP_BOOT, - early_perpage_metadata[nid]); - } -}
Currently, when memory is hot-plugged or hot-removed the accounting is done based on the assumption that memmap is allocated from the same node as the hot-plugged/hot-removed memory, which is not always the case. In addition, there are challenges with keeping the node id of the memory that is being remove to the time when memmap accounting is actually performed: since this is done after remove_pfn_range_from_zone(), and also after remove_memory_block_devices(). Meaning that we cannot use pgdat nor walking though memblocks to get the nid. Given all of that, account the memmap overhead system wide instead. For this we are going to be using global atomic counters, but given that memmap size is rarely modified, and normally is only modified either during early boot when there is only one CPU, or under a hotplug global mutex lock, therefore there is no need for per-cpu optimizations. Reported-by: Yi Zhang <yi.zhang@redhat.com> Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com Reported-by: Alison Schofield <alison.schofield@intel.com> Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t Fixes: 15995a352474 ("mm: report per-page metadata information") Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> --- include/linux/mmzone.h | 2 -- include/linux/vmstat.h | 7 ++++--- mm/hugetlb_vmemmap.c | 8 ++++---- mm/mm_init.c | 3 +-- mm/page_alloc.c | 1 - mm/page_ext.c | 15 +++++--------- mm/sparse-vmemmap.c | 11 ++++------- mm/sparse.c | 5 ++--- mm/vmstat.c | 45 ++++++++++++++++++++---------------------- 9 files changed, 41 insertions(+), 56 deletions(-)